TEMPORAL VARIABILITY IN IMMUNOLOGICAL PARAMETERS - PERIPHERAL-BLOOD MONONUCLEAR CELL SUBSETS, SERUM IMMUNOGLOBULINS, AND SOLUBLE MARKERS OFIMMUNE-SYSTEM ACTIVATION

T-cell subsets and soluble factors of immune system activation are inc reasingly used as biologic markers of disease and predictors of diseas e progression. For example, changes in CD4 cells and CD4:CD8 ratio, sI L-2R, B2M, neopterin, and IgA have been used in predicting AIDS onset and progression. We examined the temporal variability of T-cell subset s, monocytes, natural killer cells, B cells, immunoglobulins, soluble interleukin-2 receptor (sIL-2R), neopterin, and beta-2 microglobulin ( B2M) among 135 adults tested at two time points similar to 3 months ap art. The purpose of the study was twofold: (1) to assess the stability of these measures at two points in time, and (2) to investigate which parameters tend to track together over time, i.e., show significant l ongitudinal correlation. Mean population values for these immunologic parameters remained remarkably stable over the 3-month period. However , individual subjects exhibited significant temporal variability for m any parameters. Unlike observations in patients with AIDS, changes in immunoglobulins and other soluble factors were not significantly corre lated with changes in cellular subsets over the same period. However, change in B2M was correlated with change in neopterin (r = .35, P less than or equal to .0001), and change in IgA was correlated with change s in IgG and IgM (r = .44, r = .54, P less than or equal to .001 for b oth). Characterizing this temporal variability in a healthy population provides important information for researchers applying these tests i n clinical and epidemiological studies. (C) 1997 Wiley-Liss, Inc.